This invention relates to exercise devices and is more particularly directed to devices which assist persons during exercise in maintaining a correct position throughout the movement of the exercise, so as to maximize the benefits of exercise and to avoid risk of pain or injury.
This invention is more specifically directed to an exercise bar which is used in a sit up exercise and can also be used to add resistance to sit-ups. The exercise bar can also be used to add resistance in other exercises, such as lower back extensions, radial deviation flexions, or trunk rotations.
The conventional techniques for sit-ups are so-called straight by sit-ups and hands-behind-neck sit ups. Both exercises are intended to strengthen the abdominal muscles, but both are contraindicated movements because of the abnormal stress that they place on the lower back. Straight-leg sit ups can lead to lower back injury or strain, and should not be performed. This exercise abnormally contracts the hip flexors primarily the ileopsas muscles. This pulls the lumbar spine into an abnormal curve. This may be avoided only if the lower back is maintained in a flattened position throughout the movement, but that is not possible with this exercise as it is usually performed. The hands-behind-neck sit-ups exercise should also be avoided. In this position not only is there a risk of lumbar spine injury, but the cervical spine can be adversely stressed.
Recommended exercises for conditioning the abdominal muscles include the abdominal curl and advanced abdominal curl. In the former, the subject person exercising lies supine with knees bent and feet on the floor, and with the hands clasped across the chest. The subject then curls, or rolls the upper trunk and head upward towards the knees, then returns to the starting position. Advanced abdominal curls are similar, but the subject holds a weight bar or dumbbell on the chest during the movement. Both of these have the advantage that the lower back remains on the floor during the initial phase of the movement.
However, because the hands are at the chest, arm movement is extremely limited. The arms and shoulders cannot roll downward below the thorax during the movement, so abdominal muscle stress is limited only to the first few degrees of motion.
There have been a number of exercise bars and similar devices proposed as aids in performing various exercises, but none of these is suited as an aid in doing sit-ups. Among these devices are an exercise shaft for torso twist exercise, U.S. Pat. No. 3,820,781; weight support bars for knee bends, U.S. Pat. Nos. 4,274,628 and 3,370,850; and a weight bar with sliding weight tube for exercising various abdominal and dorsal muscle groups, U.S. Pat. No. 4,623,146. However, the inventor is unaware of any devices for properly positioning the subject for sit up exercises, so that the subject's lower back is kept flattened throughout the movement, avoiding strain or injury to the lumbar spine.